1. Field of the Invention
The present invention relates to an optical data link.
2. Related Background of the Invention
An optical data link includes a photoelectric conversion unit, a metal housing base member, a board directly fixed to the base member, and a cover for covering the board. FIGS. 25A, 25B, 26A, and 26B are views showing an optical data link. In the optical data link 9, a circuit board 4 and a photoelectric conversion unit 6 are mounted on a metal housing base member 2. Lead terminals 7 are supported by the metal housing base member 2, and are arranged in the circuit board 4. The circuit board 4 is covered with a cover 8 attached to the metal housing base member 2.
With reference to FIG. 26A, the circuit board 4 is directly mounted on the housing base member 2 in the optical data link 9. Silver paste is applied on the back side of the circuit board 4 so that the circuit board 4 is bonded on the housing base member 2. Since the silver paste is applied to the entire back side of the circuit board 4 to bond it to the base member 2, electronic parts can be mounted only on the front side of the circuit board 4. Accordingly, a larger board is used to increase the area for mounting the electronic components.
Referring to FIG. 26B, the housing base member 2 is made of a plurality of parts in the optical data link 9, such as parts 2a and 2c made of Kovar, and a part 2b made of copper tungsten (CuW). Since these parts 2a, 2b and 2c are assembled using silver soldering and the optical data link 9 is formed from a large number of components, the assembly is complicated. Due to the large number of components and the complexity in the structure, it is not easy to develop optical data links of a miniature size.